It sounded to me like he was going to be selecting them all anyway so I don't really see a performance advantage. And the only resources that are being used here is a single value to store the email address. I don't see a lick of difference in whether it's done in the script or not.

You would definitely want to use the database resources for more sophisticated data retrieval. But this could be accomplished by just a flat file. Unless there's more to the script than just reading out these addresses, i'd actually go with a flat file instead.